CAREER: Expanding Protein Chemistry through the Evolution of Orthogonal Non-Natural Heme:Enzyme Pairs

Expanding Protein Chemistry through the Evolution of Orthogonal Non-natural Heme:Enzyme Pairs

With this CAREER award, the Chemistry of Life Processes Program in the National Science Foundation's Division of Chemistry is funding Dr. Eric Brustad from the University of North Carolina at Chapel Hill to expand the possibilities for protein (enzyme) engineers to create new and versatile catalysts for chemical synthesis. Such protein engineering is of growing importance to academic and pharmaceutical research due to the mild and green conditions under which the biological world operates. Therefore the goal of this work is to combine engineering and evolution to create enzyme scaffolds that assemble in cells and which can incorporate building blocks not typically found in nature. This research expands the chemical diversity and reaction landscape available to protein engineers and generates new tools with broad applications in biotechnology and biomedical imaging, as well as chemical synthesis. Dr. Brustad has developed a symposium for biotechnology research to foster communication and collaboration between local scientists and students. This symposium is now expanded to promote diversity by reaching out to Historically Black Colleges and Universities (HBCUs). Dr. Brustad is also developing a hands-on educational modules for K-12 populations in rural North Carolina, serving primarily young African American and Hispanic populations.

This research introduces a new paradigm for the construction of non-natural metallocofactor proteins in cells through the creation of orthogonal heme/enzyme pairs. An orthogonal heme:enzyme pair is composed of two key components: 1) a non-natural, synthetic cofactor that is similar to heme but does not interact with existing heme enzymes, and 2) an evolved heme-binding protein that recognizes only the non-natural cofactor. This 'orthogonality' creates a new cofactor:enzyme system that can interact self-sufficiently in cells without disrupting endogenous cofactors or enzymes. A significant advantage of this approach is that it simply builds on (and adapts to) existing cofactor-binding motifs in nature to construct binding sites for metals and cofactor catalysts not typically found in nature. Scaffolds identified from this study provide robust and systematically adaptable artificial metalloproteins for green chemical synthesis as well as metal-based imaging applications. In addition, this program is focused on broadening the impact of biotechnology research by expanding education outreach to young underrepresented minorities and undergraduates students as well as fostering increased scientific communication among research institutions across the state of North Carolina.